Surveying instrument

1. A surveying instrument comprising; an installation base installed at a point which is near a reference point and. is deviated. from. the reference point and a protractor table which is perpendicular to a mechanical reference line as set for the surveying instrument and is capable of detecting a lateral rotation angle and a surveying instrument main unit mounted on said protractor table via supporting mechanisms capable of rotating longitudinally, wherein said supporting mechanisms has a lower supporting piece provided on said protractor table, an upper supporting piece provided on said surveying instrument main unit, and a longitudinal rotation. shaft which. freely rotatably connects said lower supporting piece with. said upper supporting piece, and said supporting mechanisms enables said surveying instrument main unit to set in a predetermined angle condition with. respect to said protractor table, wherein said surveying instrument main unit comprises a distance measuring unit which has a light emitting element for emitting a distance measuring light, a distance measuring light projecting unit for projecting said distance measuring light, a light receiving unit for receiving a reflected distance measuring light and a photodetector for receiving said reflected distance measuring light and for producing light receiving signal, and said distance measuring unit performs a distance measurement of an object to be measured based on said light receiving signal from said photodetector, a control unit for controlling a distance measuring operation, an optical axis deflecting unit, which is provided on an optical axis of said distance measuring light projecting unit and on an optical axis of said light receiving unit, for controlling a deflection of said both optical axes and an attitude detecting unit which has a tilt detecting unit for detecting horizontal and mechanisms for tilting said tilt detecting unit so that said. tilt detecting unit is maintained horizontally, and is configured to detect a tilting amount of said surveying instrument main unit, and wherein said supporting mechanisms have a radius of gyration with said longitudinal rotation. shaft as a center and are capable of rotating said surveying instrument main unit longitudinally downward by 90°, and said supporting mechanisms are configured to contact said upper supporting piece with said protractor table when said surveying instrument main unit is rotated downward by 90°, and in a condition where said surveying instrument main unit is rotated downward by 90°, said optical axis of said distance measuring light projecting unit and said mechanical reference line are deviated by a predetermined distance, and said distance measuring light, which is projected from said surveying instrument main unit, is configured to pass an outside of said protractor table and to strike the ground.

2. The surveying instrument according to claim 1 , wherein said control unit is configured to calculate the tilting amount of said surveying instrument main unit with respect to a vertical based on the tilting amount detected. by said. attitude detecting unit in a condition where said surveying instrument main unit is in the predetermined angle condition with respect to said protractor table, to calculate a tilting amount of said protractor table with respect to the horizontal, and to correct a measurement result of said object to be measured based on a calculation result.

3. The surveying instrument according to claim 1 , wherein said control unit is configured to calculate the tilting amount of said surveying instrument main unit with respect to the vertical based on the tilting amount detected by said attitude detecting unit in a condition where said surveying instrument main unit is in the predetermined angle condition with respect to said protractor table, and to deflect said optical axis of said distance measuring light projecting unit so that said distance measuring light is projected vertically by said optical axis deflecting unit.

4. The surveying instrument according to claim 1 , wherein said installation base is installed near a reference point, and said control unit is configured to calculate the tilting amount of said surveying instrument main unit with respect to the vertical based on the tilting amount detected by said attitude detecting unit in a condition where said surveying instrument main unit is in the predetermined angle condition with respect to said protractor table, to project said distance measuring light to said reference point by controlling said optical axis deflecting unit, and to measure a position of said reference point based on said tilting amount, on a deflection amount of said distance measuring light by said optical axis deflecting unit and on a result of the distance measurement to said reference point.

5. The surveying instrument according to claim 3 , wherein said installation base is installed near the reference point, and said control unit is configured to calculate the tilting amount of said surveying instrument main unit with respect to the vertical based on the tilting amount detected by said attitude detecting unit in a condition where said surveying instrument main unit is in the predetermined angle condition with respect to said protractor table, to project said distance measuring light to said reference point by controlling said optical axis deflecting unit, and to measure the position of said reference point based on said tilting amount, on the deflection amount of said distance measuring light by said optical axis deflecting unit and on the result of the distance measurement to said reference point.

6. The surveying instrument according to claim 1 , wherein said control unit is configured to change an irradiating direction of said distance measuring light by said optical axis deflecting unit, to project said distance measuring light to a measuring point, and to perform a measurement of said measuring point.

7. The surveying instrument according to claim 3 , wherein said control unit is configured to chancre the irradiating direction of said distance measuring light by said optical axis deflecting unit, to project said distance measuring light to said measuring point, and to perform the measurement of said measuring point.

8. The surveying instrument according to claim 4 , wherein said control unit is configured to change the irradiating direction of said distance measuring light by said optical axis deflecting unit, to project said distance measuring light to said measuring point, and to perform the measurement of said measuring point.

9. The surveying instrument according to claim. 5 , wherein said control unit is configured to chancre the irradiating direction of said distance measuring light by said optical axis deflecting unit, to project said distance measuring light to said measuring point, and to perform the measurement of said measuring point.

10. The surveying instrument according to claim 2 , wherein said control unit is configured to calculate the tilting amount of said surveying instrument main unit with respect to the vertical based. on the tilting amount detected by said attitude detecting unit in a condition where said surveying instrument main unit is in the predetermined angle condition with respect to said protractor table, and to deflect said optical axis of said distance measuring light projecting unit so that said distance measuring light is projected vertically by said optical axis deflecting unit.

11. The surveying instrument according to claim 2 , wherein said installation base is installed near a reference point, and said control unit is configured to calculate the tilting amount of said surveying instrument main unit with respect to the vertical based on the tilting amount detected by said attitude detecting unit in a condition where said surveying instrument main unit is in the predetermined angle condition with respect to said protractor table, to project said distance measuring light to said reference point by controlling said optical axis deflecting unit, and to measure a position of said reference point based on said tilting amount, on a deflection amount of said. distance measuring light by said optical axis deflecting unit and on a result of the distance measurement to said reference point.

12. The surveying instrument according to claim 10 , where said installation base is installed near the reference point, and said control unit is configured to calculate the tilting amount of said surveying instrument main unit with respect to the vertical based on the tilting amount detected by said attitude detecting unit in a condition where said surveying instrument main unit is in the predetermined angle condition with respect to said protractor table, to project said distance measuring light to said reference point by controlling said optical axis deflecting unit, and to measure the position of said reference point based on said tilting amount, on the deflection amount of said distance measuring light by said optical axis deflecting unit and on the result of the distance measurement to said reference point.

13. The surveying instrument according to claim 2 , wherein said control unit is configured to change an irradiating direction of said distance measuring light by said optical axis deflecting unit, to project said distance measuring light to a measuring point, and to perform a measurement of said measuring point.

14. The surveying instrument according to claim 10 , wherein said control unit is configured to change the irradiating direction of said distance measuring light by said optical axis deflecting unit, to project said distance measuring light to said measuring point, and to perform the measurement of said measuring point.

15. The surveying instrument according to claim 11 , wherein said control unit is configured to change the irradiating direction of said distance measuring light by said optical axis deflecting unit, to project said distance measuring light to said measuring point, and to perform the measurement of said measuring point.

16. The surveying instrument according to claim 12 , wherein said control unit is configured to change the irradiating direction of said distance measuring light by said optical axis deflecting unit, to project said distance measuring light to said measuring point, and to perform the measurement of said measuring point.